Description

Numeric truncation error in Windows DNS allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.7",
  "pubDate": "2026-08-11T17:18:39.330Z",
  "pubdate": "2026-08-11T17:18:39.330Z",
  "executiveSummary": "A numeric truncation error exists within Windows DNS, potentially allowing an authorized threat actor to execute a local privilege escalation attack.\nThe vulnerability affects the Windows DNS component, impacting the security posture of the host operating system by breaking privilege boundaries.\nSuccessful exploitation of this numeric truncation flaw enables a local attacker to elevate their execution context, gaining higher privileges on the targeted system.\nThe risk implications are significant, as an attacker with limited local access can leverage this vulnerability to compromise sensitive system resources and potentially achieve full control over the affected Windows DNS environment.\nExploitation requirements dictate that the attacker must already possess local access and authorization on the target machine.\nThe attack vector is strictly local, meaning remote exploitation over a network interface is not inherent to this specific numeric truncation flaw.",
  "technicalDetails": "The root cause of the vulnerability stems from a numeric truncation error implemented within the Windows DNS component during the processing of specific data inputs.\nNumeric truncation errors typically occur when a larger data type is cast into a smaller data type without adequate boundary checks, resulting in the loss of significant bits and the miscalculation of buffer sizes or allocation lengths.\nIn the context of Windows DNS, this improper handling of numeric values introduces memory corruption conditions, such as integer overflows leading to subsequent heap or stack-based buffer overflows.\nAn authorized attacker begins the exploitation method by interacting locally with the vulnerable Windows DNS service or application programming interfaces.\nThe attack flow proceeds as the attacker crafts specialized inputs containing values designed to trigger the numeric truncation condition upon parsing by the vulnerable component.\nBecause of the truncation, memory allocation routines miscalculate the required buffer space, leading to out-of-bounds write operations or memory corruption when subsequent data is written.\nAuthentication requirements specify that the attacker must have local execution capabilities and authorization to interface with the vulnerable Windows DNS structures.\nPrivilege requirements indicate that the vulnerability facilitates privilege escalation, moving the attacker from a lower integrity or restricted user context to an elevated administrative or system-level context.\nNetwork exposure is local, meaning the attack surface relies on local inter-process communication, local API calls, or local administrative interfaces rather than remote network exposure.\nThe post-exploitation impact allows the attacker to execute arbitrary code with elevated privileges, manipulate system configurations, install malicious persistence mechanisms, and bypass local security controls enforced by the operating system."
}